Liver, Gallbladder and Pancreas Flashcards
(28 cards)
What are the key functions of the liver?
- Synthesis: albumin, clotting factors (prothrombin, fibrinogen), lipoproteins
- Storage: glycogen, vitamin A, other
- Detoxification: toxins and drugs (lipid-soluble substances)
- Excretion: breaks down RBCs, secretes bile
- Hormone Production: insulin-like growth factor
How are liver cells (hepatocytes) arranged and what are sinusoids?
- arranged in plates separated by sinusoids, which are capillary-like spaces for material exchange
What are bile canaliculi and their role?
Small channels between hepatocytes that collect bile and direct it toward the bile duct; bile flow is opposite to blood flow
What are the functions of liver organelles like SER and RER?
- SER detoxifies drugs and makes lipids (synthesis and breakdown of glycogen)
- RER makes plasma proteins; other organelles help with storage, digestion, and energy.
How does the liver regulate blood glucose?
Insulin promotes glycogen storage; glucagon triggers glycogen breakdown to raise blood sugar
What plasma proteins are made by the liver and their functions?
- Albumin maintains osmotic pressure
- prothrombin & fibrinogen aid clotting
- transferrin transports iron.
How does the liver detoxify harmful substances?
SER enzymes convert toxins (alcohol, drugs) into water-soluble forms using MEOS or ADH pathways
What is a classic liver lobule?
- hexagonal unit with a central vein in the middle and portal triads at the corners
- Blood flows toward the central vein, bile flows outward
What structures make up the portal triad?
- Portal vein (venule)
- hepatic artery (arteriole)
- bile duct (ductule)
What is the function of the portal lobule?
Describes bile secretion
- It’s a triangular region defined by three central veins and centered on a portal triad
What is the hepatic acinus and its zones?
Functional unit defined by blood supply
- Zone 1: most oxygenated
- Zone 2: intermediate
- Zone 3: least oxygenated, most vulnerable to injury
What is the significance of the liver’s dual blood supply?
- 75% from hepatic portal vein (nutrient-rich)
- 25% from hepatic artery (oxygen-rich)
- Ensures hepatocytes receive both nutrients and oxygen
What happens in liver cirrhosis?
Normal lobular architecture is disrupted by fibrosis, forming pseudolobules and impairing liver function.
What is the space of Disse and its role?
- perisinusoidal space between hepatocytes and endothelium
- It allows exchange of substances and contains Ito cells, microvilli, and plasma
What are Ito (hepatic stellate) cells and what happens to them in disease?
- cells that store vitamin A and lipids
- In disease, they may become myofibroblasts, contributing to fibrosis
What are Kupffer cells and what do they do?
macrophages in liver sinusoids that break down damaged or old RBCs
What is bile and its function?
- aids fat absorption
- excretes cholesterol, bile salts, bilirubin, iron, and copper
What are bile canaliculi and their flow direction?
- Tiny ducts between hepatocytes that carry bile toward bile ducts
- Flow is opposite to blood.
How does the gallbladder concentrate bile?
It removes ~90% of water by actively transporting salts into spaces, drawing water osmotically
What stimulates gallbladder contraction?
Fat in the duodenum triggers enteroendocrine cells to release hormones that cause smooth muscle contraction
What are the main functions of the pancreas?
produces digestive enzymes, bicarbonate-rich fluid, and hormones (like insulin) for glucose regulation
What’s the difference between exocrine and endocrine pancreas?
- Exocrine: acinar cells secrete enzymes into ducts
- Endocrine: islets of Langerhans secrete hormones into blood
What do pancreatic acinar cells produce and how?
- produce inactive digestive proenzymes (zymogens) stored in granules
- synthesized in the rough ER and activated in the small intestine
What are centroacinar cells and their function?
Special duct cells inside acini that produce bicarbonate in response to secretin
